Transparent parts?

[mik2b]

Hi,

I'm new on this program, so sorry if I ask stupid questions...
I see that you can make some images transparent. So, where are the limitations?
There's an stylehack that make the start menu transparent... Can we add transparency to right-click menus, for example, or DialogTask windows?

What's indispensable to convert an opaque image to transparent? Only disable "Compositeopaque" and mark "composite"? BTW, what's "composite"?

Thanks (for your patience...).